ConfusedAboutEnergy.co.uk

If you have timber floors, mineral wool insulation* can be used between the joists to insulate your floor.  Assuming this is the only insulation measure installed in your house you can reduce the amount of heat loss through your floor by about a half and can therefore reduce your energy bill by about 7 or 8%.

To do this you need to be able to access under the floor via a trap door or you may have to lift all of the floor boards.  Professionally done this is an expensive job certainly costing more than £ 1,500**.  DIY it may cost only a £ 100 for materials, but if t you have to lift your floor boards, it will be a long and difficult DIY task and will probably end up costing more than £ 100 when you find yourself repairing damage caused by lifting boards.  As a DIY task we have estimated the cost at closer to £ 300 for a smaller house.

 

	Approx % energy saving	Approx energy saving per year	Gas	Electric  (Std)	Economy 7	LPG	Fuel Oil
3 bed house	8%*	1600 kWh	£ 61	£ 214	£ 72	£ 86	£ 75
DIY payback time £ 300 install cost  (3 bed house)			4.9 years	1.4 years	4.2 years	3.5 years	4 years
Payback time with an installation cost of £ 1500** (3 bed house, guess)			24.7 years	7 years	20.8 years	17.4 years	19.9 years
5 bed house	8%*	2400 kWh	£ 91	£ 322	£ 108	£ 130	£ 113
DIY payback time £ 350 (5 bed house)			3.8 years	1.1 years	3.2 years	2.7 years	3.1 years
Payback time with an installation cost of £ 2000** (5 bed house, guess)			21.9 years	6.2 years	18.5 years	15.4 years	17.7 years
**Please leave a comment if you have a better price for this it is just a “guestimate” and a better figure would be useful.